Various devices can be used to achieve the bronchial isolation of one or more selected regions of the lung. Pursuant to a lung region bronchial isolation process, at least one flow control device (also referred to as a bronchial isolation device) is implanted within one or more bronchial passageways that provide fluid flow to and from the lung region to thereby “isolate” the lung region. The lung region is isolated in that fluid flow to and from the lung region is regulated or blocked through the bronchial passageway(s) in which the device is implanted.
For example, the flow of fluid (gas or liquid) past the device in the inhalation direction can be prevented while allowing flow of fluid in the exhalation direction, or the flow of fluid past the implanted device in both the inhalation and exhalation directions can be prevented. The flow control devices can comprise, for example, one-way valves, two-way valves, occluders or blockers, ligating clips, glues, sealants, sclerosing agents, etc.
It should be appreciated that even with the implanted isolation devices properly deployed, air can in certain circumstances flow into the isolated lung region via a collateral pathway. This can result in the diseased region of the lung still receiving air even though the isolation devices were implanted into the direct pathways to the lung. Collateral flow can be, for example, air flow that flows between segments of a lung, or it can be, for example, air flow that flows between lobes of a lung, as described in more detail below.
Collateral flow into an isolated lung region can make it difficult to achieve a desired flow dynamic for the lung region. Moreover, it has been shown that as the disease progresses, the collateral flow throughout the lung can increase, which makes it even more difficult to properly isolate a diseased lung region by simply implanting flow control valves in the bronchial passageways that directly feed air to the diseased lung region.
Given that the lung can have collateral gas flow pathways in the lung that could keep the isolated portion of the lung inflated, it is desirable to occlude these collateral flow channels in order to allow the lung to collapse through absorption of the trapped gas, or by exhalation of the trapped gas out through implanted one-way or two-way valve bronchial isolation devices.